The Oxidation State of [4Fe4S] Clusters Modulates the DNA-Binding Affinity of DNA Repair Proteins.
The Oxidation State of [4Fe4S] Clusters Modulates the DNA-Binding Affinity of DNA Repair Proteins.
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DOI：
10.1021/jacs.7b07230
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发表时间：
2017-09-13
影响因子：
15
通讯作者：
Barton JK
中科院分区：
文献类型：
--
作者：
Tse ECM;Zwang TJ;Barton JK
理解DNA修复的一个重要问题是，某些蛋白质如何能够在生物学相关的时间尺度上搜索、检测和修复DNA损伤。许多碱基切除修复蛋白的一个特征是它们含有[4Fe4S]簇，这可能有助于它们寻找病变。在这份报告中，我们建立了氧化还原活性[4Fe4S]簇的氧化态在DNA损伤检测过程中的重要性。我们利用DNA修饰电极产生修复蛋白与[4Fe4S]集群在2+和3+状态下，在无氧气氛下通过本体电解。厌氧微尺度热泳结果表明，携带[4Fe4S]3+簇的蛋白质与DNA的结合紧密度是携带[4Fe4S]2+簇的蛋白质的550倍。测得的DNA结合亲和力的增加与计算出的亲和力变化相匹配，该亲和力变化与[4Fe4S]簇蛋白结合DNA时观察到的氧化还原电位偏移相关。我们进一步设计了一个静电模型，表明这些蛋白质的DNA结合亲和力的这种变化可以完全解释为DNA和[4Fe4S]簇之间的静电相互作用的差异，在还原与氧化状态。然后，我们利用原子力显微镜（AFM），以证明氧化还原状态的[4Fe4S]集群调节的能力，两个DNA修复蛋白，内切酶III和DinG，优先结合到DNA双链体含有一个单一的DNA损伤位点（这里是一个碱基错配），抑制DNA电荷传输。总之，这些结果表明，[4Fe4S]簇通过DNA介导的电荷传输的还原和氧化促进[4Fe4S]修复蛋白之间的长程信号传导。DNA结合亲和力的氧化还原调节变化调节[4Fe4S]修复蛋白在病变检测过程中合作的能力。(top)DNA介导的电荷传输信号传导是DNA损伤检测的第一步的核心，并且仅通过携带氧化（橙子）和还原（紫色）[4Fe4S]金属辅因子的修复蛋白（绿色和灰色）之间的良好匹配但不失配（表示为红色框）的DNA双链体发生。（下）当[4Fe4S]簇从2+氧化为3+时，蛋白质的DNA结合亲和力增加。
A central question important to understanding DNA repair is how certain proteins are able to search for, detect, and fix DNA damage on a biologically relevant timescale. A feature of many base excision repair proteins is that they contain [4Fe4S] clusters that may aid their search for lesions. In this report, we establish the importance of the oxidation state of the redox-active [4Fe4S] cluster in the DNA damage detection process. We utilize DNA-modified electrodes to generate repair proteins with [4Fe4S] clusters in the 2+ and 3+ states by bulk electrolysis under an O2-free atmosphere. Anaerobic microscale thermophoresis results indicate that proteins carrying [4Fe4S]3+ clusters bind to DNA 550 times more tightly than those with [4Fe4S]2+ clusters. The measured increase in DNA-binding affinity matches the calculated affinity change associated with the redox potential shift observed for [4Fe4S] cluster proteins upon binding to DNA. We further devise an electrostatic model that shows this change in DNA-binding affinity of these proteins can be fully explained by the differences in electrostatic interactions between DNA and the [4Fe4S] cluster in the reduced versus oxidized state. We then utilize atomic force microscopy (AFM) to demonstrate that the redox state of the [4Fe4S] clusters regulates the ability of two DNA repair proteins, Endonuclease III and DinG, to bind preferentially to DNA duplexes containing a single site of DNA damage (here a base mismatch) which inhibits DNA charge transport. Together, these results show that the reduction and oxidation of [4Fe4S] clusters through DNA-mediated charge transport facilitates long-range signaling between [4Fe4S] repair proteins. The redox-modulated change in DNA-binding affinity regulates the ability of [4Fe4S] repair proteins to collaborate in the lesion detection process. (top) DNA-mediated charge transport signaling is central to the first step of DNA damage detection and occurs only through well-matched but not mismatched (denoted as a red box) DNA duplexes between repair proteins (green and gray) carrying oxidized (orange) and reduced (purple) [4Fe4S] metallocofactors. (bottom) Upon the oxidation of the [4Fe4S] cluster from 2+ to 3+, the DNA binding affinity of the protein increases.
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影响因子：
15
作者：
Grodick, Michael A.;Segal, Helen M.;Zwang, Theodore J.;Barton, Jacqueline K.
通讯作者：
Barton, Jacqueline K.
影响因子：
3.9
作者：
Boal, Amie K.;Yavin, Eylon;Barton, Jacqueline K.
通讯作者：
Barton, Jacqueline K.
影响因子：
2.9
作者：
CUNNINGHAM, RP;ASAHARA, H;EMPTAGE, MH
通讯作者：
EMPTAGE, MH
影响因子：
56.9
作者：
Gari, Kerstin;Ortiz, Ana Maria Leon;Boulton, Simon J.
通讯作者：
Boulton, Simon J.
影响因子：
4.8
作者：
Agarwalla, S;Stroud, RM;Gaffney, BJ
通讯作者：
Gaffney, BJ